Automatic expansion valve



Aug. 21, 1923.

E. J. RADTKE AUTOMATIC EXPANSION VALVE Filed March 5 1921 Arma/VHS.

Patented Aug. 2l, i923.

EDWIN J. RADTKE, OF MILWAUKEE, WISCONSIN.

AUTOMATIC EXPANSION VALVE.

Application led March 5, 1921. Serial No. 449,706.

To all whom it may concer/n:

Be it known that I, EDWIN J. RADTKE, a citizen of the United States, residing at Milwaukee, county ofk Milwaukee, and State of Wisconsin, have invented new and useful Improvements in Automatic Expansion Valves, of which the following is a specification.

This invention relates to automatic expansion valves, and is particularly directed to a valve adapted for refrigerating appa,- ratus.

In valves of this type in which the pressure in the expansion or low pressure mains governs the opening of the valve a great deal of difficulty has been encountered, due to several distinct causes. One diiiiculty has been the sudden opening of the valve and the sudden closing of the valve as distinguished from a gradual minute opening of varying extent. This sudden opening allows a surging of the refrigerant in liquid form from the high pressure side to the low pressure side of the apparatus without allowing sufficient time for the vaporization of the liquid. This obviously causes a decrease in the efciency of the apparatus and a raising of the temperature for the same amount of energy consumed by the apparatus.

A further harmful effect resulting from this defect is the gradual iilling of the cooling coils with the liquid refrigerant while the machine is shut down, so that when the machine is again started it is necessary to pump out all of this liquid refrigerant from the cooling coils before vaporization can even begin. Applicant has discovered that one of the reasons for this defective operation is due to the improper proportioning of the valve to the diaphragm and the selection of a valve having certain characteristics in place of a valve particularly adapted for cooperation with the diaphragm.

A second cause which results in lowering the efficiency of the apparatus comes from the pitting of the valve surfaces, due to the chemical and mechanical action of the liquid at the time that it changes into gas. This pitting is localized with valves of the prior constructions, and eiiects a roughening of either the valve or the valve seat which prevents good seating of the valve at any time, and also causes a more irregular working, or movement, of the valve than is permissible in machines of this type.

It is to overcome the above noted defects that the present invention is designed, and 1t 1s therefore an object of this invention to provide an automatic reducing valve which will greatly increase the efficiency of the refrlgerating apparatus; to produce an automatic expansion valve in which a gradual, graded opening of the valve is always secured when the valve functions; to provide an automatic expansion valve in which a .secure seating is effected, and in which leak` lng of the refrigerant into the low pressure mams while the machine is idle is prevented; and to provide an automatic expansion valve in which localized pitting is prevented.

.Another object of this invention is to provlde an automatic expansion valve in which the valveis provided with a plurality of faces spaced from each other to form a series of expansion chambers adapted to permit vaporization of a liquid and a reduction of pressure step by step as the fluid passes from the high lpressure chamber to the low presure cham er, thereby to prevent wiredrawing of the liquid and consequent pitting of the valve faces and valve seat, whereby a complete and perfect fit of the valve faces and valve seat may be insured.

Further objects are to provide an automatic expansion valve in which the valve and valve cage may be removed without dief turbing the diaphragm or other portions of the valve; in which the valve may he removed fromthe valve seat without removing the seat; in which means are provided which prevent the gathering of entrained grit or foreign material about the valve or valve seat; and to provide means whereby such entraincd grit or foreign material may be trapped and readily removed from the apparatus.

An embodiment of the invention is shown in'the accompanying drawings, in which Figure 1 is a vertical sectional view thru the automatic expansion valve.

Figure 2 is a side elevation taken at right angles to Figure l. v

Figure 3 is a bottom view of the structure shown in Figure 1.

Figure 4 is a view on a larger scale of the valve cage removed from the rest of the apparatus, and with a portion of the screen broken away.

Figure 5 is a view on a larger scale of the valve removed from the apparatus.

The expansion valve comprises a pair of main'members comprising` a top portion 1 and a bottom portion 2, the top portion 1 being substantially bell shaped and hollow thruout its major extent, and the lower portion 2 being provided with the necessary orifices and recesses hereinafter described. A steel diaphragm 3 isheld between the members 1 and 2, and is tightly gripped between the flat annular ring 4 of the bottom member and the rounded annular ring 5 of the top member, such members being provided with annular grooves 6 'and 7 just outside of the outer periphery of these annular portions 4 and 5. Clamping bolts 8 pass thru the anges of the members 1 and 2, and cause the annular projections 4 and 5 to tightly bind upon the steel diaphragm. Upon the upper side ot the diaphragm a disk like plate 9 is iositioned, and is provided with a vertica periphery 10 and an' annular rib 11 upon its upper surface. The member 1 is correspondingly provided with a vertical wall 12 adapted to co-operate with the vertical face 10 to guide the member 9, and with a horizontal annular face 13 adapted to co-operate with the upper surface of the rib 11 to limit the upward motion ot' the member 9, and protect the diaphragm from excessive upward deflection,

A spring 14 bears at its lower end upon the disk 9, and is retained at such lower end by means of the central hub 15 termed upon such disk. At its upper end the spring bears upon a disk 16 which is correspondingly provided with`a centering hub 17 which co-operatcs with the spring to maintain it in correct position. The position of the disk 16 is controlled by means of the threaded spindle 18 which sockets at its lower end in such disk, and is provided at its upper end with a hand wheel 19, whereby the correct adjustment may be readily given it. It is locked in place after the adjustment has been secured by means oi" a lock nut 20.

The lower member 2 is provided with outwardly extending bosses 21 and 22 which are in turn provided with the openings 23 and 24 threaded at their exteriors to receive suitable pipe fittings. The member 2 has a central cavity 25 which, at its upper end, is contracted into a small threaded opening. This opening communicates with a conical shallow recess 2G immediately beneath the diaphragm 3. It is to be noted that surrounding the contracted opening adjacent itsuppcr end is a boss 2T. which is provided with a series of milled slots 28. An opening 29 places the recessed portion 2G in communication with the o iening 24.

A valve cage 30 is provi ed with an upper shoulder 2,1. and a reduced upper threaded portion 32. such shoulder and threaded porvtion adapted to co-operate respectively with the shoulder 33 and the reduced threaded opening 34 in the member 2, a fiber gasket of any -desired thickness being placed hetween the shoulders 31 and 33 to secure the correct vertical adjustment of the valve cage. The lower portion of the valve cage is provided with a'hexagonal head 35 adapted to co-operate With a suitable wrench to secure the desired adjustment of the valve cage. This valve cage is bored out centrally so as to form the relatively small upper opening 36, a conical valve seat 3T and an enlarged lower opening 38, the last mentioned opening being threaded at ils bottom edge, as indicated at 39. A threaded plug 4() closes the lower end of this opening, and is conveniently provided with a hexagonal head 41. An exterior annular groove 42 is formed in the valve cage adjacent its lower portion,.'and such groove is placed in communication with the enlarged opening 38 by means of a series ot' relatively small holes 43. A fine woven steel screen 44 is wound about the valve cage and covers the recess or groove 42. such screen conveniently having its ends soldered.

The valve comprises a central spindle 45 which has integrally formed therewith the valve portion proper, which latter comprises three aligned conical surl'aces 46, 47 and 48, separated by a series of grooves 49 and 5() adapted to act as expansion chambers. 'The lower portion of the valve body proper is cylindrical as indicated at 51, and the bottom portion is provided with a slotted hub 52` adapted to serve the double function of positioning the upper end of the spring 53, and ol providing means whereby the valve may be readily manipulated when grinding into position with respect to its seat. The upper portion ot Vthe spindle 45 is rounded as indicated at 54.

It is to be noted that this valve is of a material diameter very much in excess of the'size required for the free delivery ot the liquid past the valve. lt will be seen that the valve merely opens a very minute amount, and thereby allows a suliicient flow of liquid as distinguished from a -valve that has to open a material dist-ance to allow the Sallie volume of liquid to pass. A further effect that is secured by this particular type of valve is the atomizing action that takes place at the line where the conical surface 4G meets the abrupt fiat surface 55. Thus a very thin converging film of liquid passes between the valve and the valve seat when the valve is open. and such liquid immediately arrives at the tree open space above the flat surface 55. Atomization takes place and the vaporization ol the liquid is very much enhanced.

In order to prevent damage to the dia`A phragm by the relatively small Spindle portion 45, a cap 56 is loosely positioned over lll) its under side contacting with t the boss 27, and against the diaphragm 3, e curved upper surface 54 of the valve spindle:

The lower end of the opening 25 1n the member 2 is closed by means of a cap 57, such cup and the corresponding portlons of the member 2 having stepped faces, a suitable gasket 58 being positioned between certain of such faces, if desired. I his cap is provided with outwardly projectlng ears 59 thru which bolts G0 pass, such bolts of course being threaded into the body` of the member 2.

It will be seen that by the lower portion of the cap 57 and the co-operating opening 25 a relatlvely large settling chamber 1s provided, the screen 44 also aiding in preventing the entraining of any sediment carrled by the liquid. The cup shaped cap 57 may be removed and the sediment washed out whenever it is found that such operation is necessary.

It will be seen that an automatic expansion valve has been provided in which a very minute motion of the diaphragm and of the valve is required in order to allow a, lm of liquid to pass in sufficient quantity to suit the requirements of the refrlgeratlng apparatus. It will also be seen that the valve freel. floats upon the spring 58, and may aline itself with its bearing independently of the' rest of the apparatus, the spherical surface 54 of the spindle aiding in this perfect freedom in aligning.

It is to be noted that the valve, spring, and valve cage may be applied or removed as a unit. This type of construction is particularly applicable to the renewal of worn parts of valves which otherwise would -be in perfect condition. It is, therefore, contemplated removing the worn valve and valve seat in an old structure and replacing the worn parts by the valve cage which, it is understood, carries the valve, the spring, and the ltering strip 44. The unitaryA construction of these parts permits a quick and easy renewal of the worn parts of valves now in service and the adjustability permits accurate positioning of the valve cage and associated parts as a unit to secure the desired adjustment without disturbing the adjustment of other parts of the old structure.

It will also oe seen that the sticking and uncertain' action of the valve is wholly eliminated by the peculiar construction employed as the valve is not rigidly secured to the diaphragm, nor is it guided by anything except its seating surface. It will also be noted that the strains due to the upward motion of the diaphragm are not transmitted to the valve, and consequently exb cessive pressure is never exerted by the valve upon its seat.

In actual tests it has been found that from ten to twenty de in smallv refrigerating plants where this valve is employed as the l reducing valve than has heretofore been-possible whenv any ofk the prior types of valves were used'in such refrigerating apparatus. It has also beenV found that when the ma` chine has remained idle for a great number of hours that the vacuum on the low pressure side has remained approximately conetant.

I claim:

1. In an automatic valve comprising a bo y\portion having lowand high pressure cavities and a diaphragm adapted to be actuated from the pressure in the low pressure cavity, the combination with said body portion, of a cylindrical valve cage disposed within the hi h pressure cavity and having a centrally dlsposed opening communicating with the low pressure cavlt and an annular groove upon the outer perlphery of said cage provided with apertures communicating with said opening and the high pressure cavity, a screen disposed about said annular groove adapted to filter gases passing therethrough, means for closing the lower end of said central opening, an elongated valve seat Within said opening, a valve within Said central openmg, said valve com rising an elongated bearing portion provi ed wlth a pair of annular grooves,l a stem adapted to Contact with said diaphragm, and a hub having a transverse slot, and a spring disposed about said hub adapted to maintain said valve stem in contact with said diaihragm, whereby said spring and valve may e qulckly removed and said valve may be ground into position upon its seat.

2. In an automatic pressure reducing valve, the combination with al valve cage having a central opening therethrough, an annular groove upon the outer periphery of said, cage, and apertures communicating with said opening and groove, of an elongated valve seat within said opening, a valve within said opening having an elongated bearing surface provided wlth a series of annular grooves, a rstem upon one end of said valve adapted to extend outwardly from said valve cage, a lug upon the other end of said valve provided with a transverse slot, a removable plug adapted to close the lower end of said valve cage, a spring disposed between said plug and said valve adapted to position the valve upon its Seat, and a filtering screen disposed about the annular groove on said valve cage.

In an automatic pressure reducing valve, the combination of a valve having caring surfaces subdivided by a series of grooves, a ported member having a valve seat spanning the grooves and against which said bearing surfaces may seat, and means rassure reducing for positioning said valve upon said valve seat. v

4. An automatic pressure reducing'vulve structure comprising a body portion having low und high pressure cavities, the combination with smid body portion, of an elongated vnlvc scat within said body portion and disposed hctweon said 10W and hlgh pressure` cavities, a valve having u plurality of faces, said faces being spaced from each 10 other to provide a set of expansion chambers adapted lto permit vaporization of a liquid and a reduction of the pressure step by step as the fluid passes from the high pressure chamber to the 10W pressure chum- 15 EDWIN J. RADTKE 

